This work focuses on the mechanism of acute antibody-mediated rejection leading to graft loss and the mechanisms of accommodation permitting graft survival in ABO-incompatible kidney transplantation. As previously noted, accommodation occurs only with (i) post-transplant suppression of glycosyltransferase, a product of ABO histo-blood group genes in the graft and (ii) prevention of antigen-antibody reactions and delayed hyperacute rejection due to reduced antigenicity of enzyme-regulated histo-blood group antigens. This article discusses the mechanism of ABO histo-blood group glycosyltransferase suppression. Accommodation is always established in successful ABO-incompatible organ grafts and ABO-minor mismatch bone marrow transplantation. In the former, accommodation develops even though ABO histo-blood types of the recipient and the donor are incompatible. In the latter, infusion of donor-derived bone marrow causes the recipient's blood to be eventually replaced by blood of the donor's type. However, the recipient's organs retain their original tissue type. In successful bone marrow engraftment, accommodation is established regardless of ABO-incompatibility. In organ transplantation the recipient's ABO histo-blood type regulates the graft's ABO histo-blood type, while in bone marrow transplantation the new ABO histo-blood type from the donor suppresses and regulates the ABO histo-blood type in recipient organs. In other words, bone marrow-derived histo-blood type regulates the histo-blood type of the organs.